Heat Loss

[Illernoise]

I've read and read and couldn't find anything with this specific problem so I figured I'd ask and hopefully someone has had the same problem and found a solution. Saturday at 1 am my heat is working completely fine. Blowing nice hot air. I go to bed and get up at 5 am. After warming up the truck I come out to a cold truck. WTF...so I drive to work and it's blowing semi-cool air. My ride is about 5 minutes...after 45 minutes or so I get back in the truck to go home and the hot air is blowing...nice! ... Until the truck gets warmed up. So..anyone had this problem before? My heat works until the truck is warmed up. It blows nice, hot air...then about 175-180 degrees the air drops off and around 190 it's just cool air. My selector switch won't push air on 1 and 2 so 3 and 4 are the only way air comes through, if that's any problem. Hopefully one of you has had this problem and found a solution. Thanks guys!

[Jay-Sliver]

One of 4 things..

Either there is air trapped in the system (heater core is air locked)

OR

Bad Intake or Head gasket, allowing air to enter the cooling system

OR

Heater core plugged up, but highly doubt it if you have heat at first then it gets cold

OR

Rad Cap gone bad



When you DONT have heat, grab the heater core lines, and see if one is soft and empty feeling...it will be the line that runs back to the top of the water pump that you want to feel, its the return line and will be the line that will get soft and feel empty.

Jay

[dave1182]

or the heater control valve is bad.

[Illernoise]

Radiator cap went to the wayside. Replaced and coolant was put back in and she's hotter than a camels ass now

[XTREME80]

Did you check for leaks.... If it wasn't in the overflow tank then the coolant is going somewhere.... Or i could have been just that low...